🔍 Key Concepts

• How portable dry chemical extinguishers are pressurized and stored • Difference between stored-pressure vs. cartridge-operated extinguishers • What actually forces the powder out of the extinguisher cylinder

💭 Think About

• Think about what must happen inside the extinguisher to push the dry chemical powder up the hose and out the nozzle. • Which options describe a reliable, controllable source of pressure that can be built into a small, portable unit? • Eliminate any options that would not create enough or consistent pressure to throw powder toward a fire.

✅ Before You Answer

• Ask yourself: is dry chemical powder likely to flow by gravity alone, especially through a hose and nozzle? • Consider whether a hand pump is common on standard portable dry chemical extinguishers you see on board vessels and in buildings. • Think about whether mixing water with the chemical is how dry chemical units are designed, or if that sounds more like a different type of extinguisher.